One Boy Dead, One Missing in Yosemite National Park

iStockphoto/Thinkstock(FRESNO, Calif.) -- A boy who was cooling off with his family in Yosemite National Park's Merced River has died after he and his still-missing younger brother were swept away.

The brothers, 10 and 6, were visiting the park this week with their family as part of a group from the Calvary Church in Anaheim, Calif. Members of the group decided to bathe on the hot day in a rocky and hazardous section of the river when a strong current carried the boys away.

The 10-year-old boy, who has not been named, was pronounced dead on Wednesday. Crews and dive teams are still searching for his 6-year-old brother.

Another visitor at the California park was able to grab the 10-year-old from the water about 150 yards downstream from where he was swept up, but efforts to revive him were unsuccessful, ABC News affiliate KGO-TV reported.

The church group had stopped to bathe at the national park's Vernal Fall Footbridge, where the park's Vernal Fall is first seen.

Last summer, three friends cooling off in the pool above Vernal Fall were swept to their deaths.

Yosemite Park Ranger Scott Gediman said the river can be deceptive.

"This is a situation where on warm days, the river is inviting," he said. "And though it's only ankle deep, the current is deceiving, and so as they were wading out there and playing in the river they got swept away."

"We don't feel the area is dangerous, but we have low water levels coupled with warm temperatures so people certainly want to swim, but people certainly have to be careful," Gediman added.

The incident comes amid a separate death at Yosemite. A California tourist died after contracting what is believed to be hantavirus pulmonary syndrome, a rare rodent-borne disease, while visiting the park.